I was attempting to create an encounter with a Champion, which is a monster whose stat block is given in Dungeon of the Mad Mage.

Despite owning the full DotMM digital book and therefore supposedly having its monsters unlocked, it's not giving me the Champion stat block. It's telling me that I need to purchase it from Monsters of the Multiverse.

I assume this is a glitch as part of the retiring of Volo's Guide and Tome of Foes. Hopefully not every monster from every adventure that also appeared in those books was affected.

EDIT: Well I'll be darned. Right after making this post I tried again and now it gives me the legacy stat block. Guess the system just needed some time to update everything in my account, since I only bought the book a few hours ago. Mods, feel free to delete this thread. Thanks!